Propeller



Jan. 12,1943. M. R. MULLEN PROPELLER Filed oct. 25,1938 4' sheets-sheet 1 Jan. l2, 1943. M. R. MULLEN PROPELLER Filed ot. 25, 1938 4 Sheets-Sheet 2 R, a n mm W N 1w A. w

Jan. 12, 1943. M R, MULLEN PROPELLER INVENTOR: M17o/zR-Mz1//e/z,

A TTORNE YS Jn. 12, 1943. M R, MULLEN PROPELLER Filed oct. 25, 1938' 4 sheets-sheet 4 IN @E N .A-.I\ Exxnnr.: .www NNN I N VEN TOR:

A TTORNE YS um'rED o "raggi-mv" i This invention relates to propellers and.'l more particularly to a propeller for aircraft and the like, the pitch of which may be varied or controlled in accordance-with the operating conditions.

v In the propeller art at present there are various forms of. constant speed propellers none oi' f is provided with a reversef 'as weil es a forward control.'

It is a further object off-the present invention j to provide a speed responsive governor which :5 will prevent the engine from overspeedingdun' 'ins adiustmets' of pitchbv v .srrins fueiieed -oo the j me so willen the 'r'nrjopcliei-in.alerones.f

ave variabiepicon. 1n both forward or zero piteh. "to provide' 'er which can be' called the forward or pullingquad- 10 vWilllillliiiifvil' 838,19 @we 0581141- whlch has a safe constant speedror speed respon-Q :Itis' flllthefpblecl'g-oi the Presenimvmmn pcnsive l governor J which `It is a. further object bf rant, and also in the negative or reserve 'pitcln the reverse quadranti where engine povvertends" to push the plane backward. It is truethat dmple reversing of a switch or aset 'of valves willg: cause the governor tohave the opposite eiiectfto red mure@ Df. normal and, by'proper manipulation,l serve-.to operate the blades in negative pitch. This,- how.- ever, requires both skill andY goodpluck to'fop'erate safely.- For instance if the propeller has beenopenting normally in constant speed forwardandthe' switcher set ot valves-is reversed with the intention ot operating in reverse pitch, a slow engine will cause the propeller to swinztowardthe lull feathering position instead di toward zero. The' result might be fatal.

1t is en object of chem-esenti invention tot f Vprovide a system-for varyingthe' pitch'ofthe f5; propeller which permits of a widevariation in adjustment of the pitch oi' vthe propeller, It is a further -object; ot this invention to providea systemy for varying'- thejpitch ola pro peller which may be operatedyautomatic'allyrat constant-speed.. Itis a further object oi' present invention to provide a system for controlling the variation i f .Dilh o! a propeller'.l embodying control. by -a speed. responsive governor; 1

It is a further lobject oi 'the' present invention to provide a controllable pitch propellerwhich may be adjusted so that, the' power 'oi the'engineis used to produce a-propeliing eiiect or a bralring effect as desired.

to provide a 'controllable pitch propeller" which may be shifted as desired' to .a fullieatherin'g position. I- i, l It is a. further object of the present invention to provide a controllable pitch propeller'which may be fully and safely controlled over a'wider range of movement than has heretofore been attained. l

. It is aurther object of the present inventiom f-'r'everse' quadrant. n

zl'sfiormin's port-hereofg'and in which:

gz -'Fls ij is ascihe'rnaticv view-ortho propeller with the control'mechanlsmlset for normal semerinthe 'reverse guadrsnt;

T135- Bliss schematl witlicontrois-set vloi-no rnull operationinftiije Fim- 4 l schematic vhmiinlthe villen-imm rod operated waived. ;and propeiierzpltcli) .in the. 'with the piiotoperated controls 'setter reverse f quadrant operation` Figi 5 is aschematic proponer pitch); in` the reverse quadrant 'sind .fforw'ard quadrant;- 1

is :1 schematic diag'ram'o'fa modifica,-

" tion ot myinvention invwhi'ch apipe line not con.. `trollen by the lovernorls-iedto ensure. quick-' and immediate shifting of the blades' v from the L' zlorwardquadrant to the reverse-quadrant. or vice versa, regardless of the `position of the gov- A, gear pump is shown although, or 1 j course,variousothei' forms of Dumps myiieyusdi I to provide a controllable pitchpropeller which 55 if desired. It shows the various valves,

emol?.

Itls-a furtheriobieet' o t invention rito which fsemwelrgnowf' f orof'theol'ndes to theiulleieathens Fie. 2 is a schematic-view or'tnopmbnetwth 30 the. Pilot, ,mntrols set' for forward oper.

diazramio'i Propeller l A er .with the pistonjipiston rod operated valves and 'the present wenn me pilot operated valves ser for operatioojio the `in forward.

' -'scription and herein ,contained' ar'ejile lustrative 'mereh'g' and that various changes and modifications maybe m'ade inthe structure dial closed without ,departing from the spirito! the .shift the position of thel leading edges of the;

blades 5l landchangethe pitch ofthe propeller.;

` -as hereinafter'more fully referred to'. I f' fx The system of the'present invention'has'por'-35` tions thereof preferably-carried on a iixed por-fev :tion of the planeadjacent the propeller'shaft I I .-f-f- 1 and portions movablewith the hub and carried in part within a housins'securedzto the hub. A'. governor-G is driven by thel propeller shaft 3i 0.-

in any suitable inanneri'-.- .V i

'I variable,Y 'reversible pressure oil pump lil which is' driven-by the engingigandcontrolled by the "governor G, is connectedr sump or tank; check valves l5 `and 88 in parallel withpressure relief `valves so arrangedas to permit oil tobe drawn into. f f the systemthrough pipe si from the o il sumpor Y part of the system'tothe 'rotatable portionoff peller drive shaft Y type oi valve designedto'lprefvalves setA for reverse invention'.

A Referring more particularly to the f.` drawings,

the propeller 'shaft-3|" which is driven by' 25" gine (not shown) has ajhub typically illustrated and movable therewith within whichthe bladesff 5|! of the propellerare carried. The bladesl il maybe mounted in the hub 'in any' desiredmaii-f 'so ner and are sitably lournaledmr rotation tofl The governor G may ,be l desired true.

I but includes. arnovahle portion," 2, Vwhich changes its position; lin. 'itccordance .with the.

' change of speed abveo below a selected. level,"5f and-provisions for changin'g'zfthe speedlevel. as 1 f j at lill.v The governor G, forv any particular setting 4offspeed IeVeL-controls'the position of a rmovable'meinberrsuc.h drive shaft it of a pump lili-"The :movable'member or shaft ilis '50' adapted foralteringthe quantity and directions-' z of oil and' oil pressure producedby-pump il; as

hereinafter more nxlly pointed out, and it is also.:

-equipped toreduce fuel suppiyingcase creverspeeding, and to switch-ofi' ignition incase vo1V extreme over-speeding.

A suitable source of oilv pressure lauch itsf'theV g to pipe lines 20, 2l, 32,'.

to be" discharged through pipeline 9i to theoil tank.

the system through". bushes l2 and 3l at the prio@ passages. and 32.

-The oil is.carried tahug h the rotatable drive '(5 'Valves' It fand 1l are controlled by movement. fsh'ait or rod 4t through pin l2.' bracket springs and vattached to'rod Il,

Amxedtapia sz is bracket ".4, f Movement fof thepiston Ii, -,rod Acauses' bracket BB to-slide 'along rod I6, pressing asainst and movinsY Spring. 5l or ES-until said" rod I6, rod lil and arms 0i xiiove stems of valves and Il to'forwardorireverse position asde-' aired. Excess movement of bracket 55 only serve to, further compress spring or. y In Figures 6,' '1 and 7a there is show nmuch' 1 f of the materiales in the precedingiigures with' certain modificationasubstitutions and additions'.` Gear pump i2! or other single-direction flow oilpump'is'substituted for variable direction-now oil pump Il. Flow iromthe Dump i2! takes place 'into one ofthe twosides oi 'the system throu'ghl governor controlled valve |2l. Another governor controlled valve 'ill regulates discharge fromv es :n and so beine manera omrwam actuating meer cylinotherend,`. to spring I which normally holds rod 'iand-valves 39, 86j, 14, and 33 in the forward 'positionr This ring i, being attached'to the 1'9- ating section ofthe system, rotates 'with th e On the stationarin4 or-enginai sideV is ring t and rod'lor. cable 3 which the pilot pulls to re` and vthrough them their-stems. which stems ",*thatis connected to rod I6.. vTo' rodfli are attached the outer'ends of springs." andi!! it, 1pm'. liz-.1

'either side' or the systeminto pipesl and ythe Governor shunt oi the position ofthe governor G. Flow through pipe ill-is possible only when the pilot-operated The newly designed valves iii and Ill are for the purpose of preventing the flow of the governor 8i b'ymeans 'of the pipes. 4or drilled pas# sages. li and 32 and throughan interconnected systemjofvalves or other control mechanisms to -L a'propeller 'blade actuating` cylinder Il.; Three-way valves 33 and 14 'and valves 6I and j l! arecontrollable bythe pilot' through rodor -u;jcneeavaivein permits discharge of :outboardffor reverse actuating side of Presmre of :the o salamander u accuate' 4piston .licensing-rod to move -pin I2 within slot Il oi gear cylinder 4l attached to gear 14|;

8 being gearedrthroughgears 49 to 'the huhA ends of, any' desired number of'propeller blades 59; of which, for, convenience; only one is shown. x'- -'I. Three.vva v valves 33 and 'Il andvalves 3l and- IQ have the .arms #attached to their stems.

jEach :of these ar'ms'fl is fulcrumedatonejend :preferably cont'ainingaI ball bearing S and, at its arel fulcrumed to. rod

tipe m'.ma n ofthe oi' causing a quick shift of the propeller blades. from quadrant to quadrant regardless 'valves "JL-and I3 are set for operationV ,in quadrant vvhile'the piston-operated' valves llandl aresetforope'rationinthe otherquad- RQ Pipe lines Y2i"and@N'c'on'neet'the stationary- 70' rant.j '1his fiow is-.oontroiied by an additional-- pilot-'operated valvej 'in and piston operated "'valvesl andi".

-in forward, and piston operated Nowassume that thepilot has of cylinder Il, forcing piston Il inward, causing a,sov,s 4o e pipe u, to the outboard or reverse operating side- If the. engine happens be running "fast, or

' is speeded-up by the pilot. pressure will be built piston rod I3 to force'pin 3 3 along slot I3 of gear i cylinder 41 thereby turning blades Il! in the direction of pitch, reducing the bite of said blades and consequent load on the engine, until the latter speeds up, causing governor'G to bring pump |I to neutral position bringing blade movementA toanend. a l

The oil ejected from the inboard or I forward ,1.0

actuatingend oi' cylinder M passes through. pilot voperated valve 33 orcheck'. valve 33. pipe 3l,

24 topump I0.

pilot operated velveu, pipe ambush il end pipe EndofSequenceZ.v l?. y I t Sequence 3, see Fig. `?.Norm al forward ope'ration-Engine speed low. pitch decreasing to bevlow zero-Pilot operated valves 33, 33, 14 and 33 f in forward, moving to reverse.

If, for any reason, pistons, blades v50, wouldy tend to pass zero, valve 1l, which had been open to that-point, would be closed as shown in Fig. l1.

valves 33- and shutting-oil' the oil supply'to the outboard, or

reverse operating end of cylinder M, effectively stopping further .reverse movement. If it were not for the presence of check valve 33 in parallel,

the closing of valve 13, after' valve 66 had already been closed, would have permanently locked the system. Check valve 33, however, permits. oil to leave the outboard, or reverse operating, side of cylinder 44 when increasing engine speed causes oil to be fed into the inboard or forward oper?v 'ating end of cylinder 43 moving piston 4 8, piston rod 4 0. intermediate mechanism 52,33, li and I3, valves 10 and 33 vto forward position beginning Sequencel. 'v

End of Sequence3. f

about to land, the plane and wishes to u se the braking. eifect of having the pitch of the blades versed propeller blades, less load on and the'engine will tend to speedup.,

Governor G will move drive shaft of pump'l 'upon .the left-hand sideofpump |0. Oil will travel through pipe 2l,'bush 30, pipe 32, valve 33,

pipe 11, pipe 13, valve 33 and pipe 35 to. the outboard or .reversing end of cylinder M.

-Oil from the-inboard or forwardend of the cylinder M'cannot be ejected through closed valvesor'll." If it were not for. the check valve 33 in' parallel with valves 33 and 33. there would-be ,'ap'ermanent locking of the system.`

However'the check-valve- 33 is in'the system and does'furnishan outlet through pipes 3i, valve to pump l0. This il, pipe 3|, bush 32 and pipe 20 Detlnitspiston and intermediate mechanism yI2, Il,... AIl and `"to lnove the blades Il to re` verse quadrant, carrying the piston .operated operation-inthe reverse quadrant.'

"valves and Il to reverse positions for continuedV -1 e End of Sequence 5.` v

Sequence 6, 'see Fig. 3.-'Normal reverse operation-Engine speed high, pitch changing out-f' ward to increasing reverse pitch-Pilot operated valves", 63,14 and 33 clamped in reverse, and piston operated valves 36, 10 in reverse. Assume the plane is landing and the engineerengines .are used with reversed propeller"bladepitch fori as me 'forward speed er u ie piane is reduced there willlfbe'iless. air pressure against the 11ethe engine Il upward causing pistons |3 to suck oil in from 'pipe 33 forcing the oil into pipe 2l. bush 33, pipe 32, valve' '33, pipe 11 .pipe 1 3, pilot operated valve 33 and pipe 33 to outboard or reversingA end of landed, or is A' '53 reversed so that withthe engine moving in the same direction. said blades will be pushing backward'instead of pulling forward.'

The pilot will Dull rod or cable 3, ring 4,' engaging bearing 5, ring 6, rod' 1, valve arms 8, moving valves 33, 14, 66 and 33 to the position for operation in the negative or reverse quadrant. Pistoneoperated valves 38 and 10 will be in position for forward operation.

Sequence 4, see Fig. 4.-Shift from forward quadrant to reversequadrant operation-Engine speed low, no pitch change-Pilot .operated valves 33, 63, 'Il and 33 in reverse, and piston operated lvalves 36 and 13 forward.

If the engine happens to be running slow there will be no movement of the blades. 50 because.

-cylinder 4l, forcing piston 45, piston rod ,-pin

' nin a .reverse direction causing pin to turn gear cylinder 41., gear 43, gear 39' and bladesv Il in the reverse direction, taking .a bigger bite of.

the air, increasing the engine load, slowing engine to desired constant speed where shaft |301 pump I3 is moved bygovernor G to dead center,

ceasing pumpingefiect of pump I0 and ceasing further movement of blades 50.

Oil forcedout of forward operating' end of cyllnder M passes through pipe 4|, piston operated valve 33 or check valve 38 to pipe 35, pipe 18, pilot operatedvalve 1l, pipe 3|, bush 32 and pipe 2 3 to tion-Engine speed low-Pitch changing inward .to decreasing reverse pitch-Pllot operated valves 33, 63, M and 33 clamped in reverse, and piston v -operated valves 33,10 in reverse.

while pressure built up on the right'h'and side.A

pipe 3|, pilot operated valve 14, pipe 1B and to pipe 3i, itA cannot pass piston-operated valve 33 or pilot operated valve 39, therefore the output.

of the pump will be discharged through pres- A of pump I0 could pass through pipe 23, bush 33,

sure release valve l31 and pipe 3| to oil sump' I or tank. The other side of Vpump I0 will draw oil through check valve 33 and pipe 3|, from oil sump on tank.

End of Sequence 4.

Sequence 5, see Fig. 4.--Shift from forward quadrant to reverse quadrant operation- Engine speed high, pitch changing from forward through zero to increasing outward or reverse pitch- Pilot operated valves, 33, 63, 14 and 33, clamped,

in reverse, shaft, and piston operated valves 36 and 10 in forward.

The pilot regulates plane speedin landing b y varying fuel feed to engine or e ngines."' y vHe-xnay so cut throttle asto reduce reverse pitch of blades, in which c ase the following will occur:

Governor G lowers pump drive shaft i3 to beyond center causing pistons Il todraw oil from pipe 3| forcing it to pipe 20,'bush 32, pipe 3|;

pilot operated valve 1I, pipe 13, pipe 35, pistony operated valve 36 and pipe 4|. to the inboard or forward operating end of cylinder M, moving piston 43 and blades 50, etc.,'ir. a forward direc'- tion or toward zero in a direction of decreased pitch.

Oil from the outboard side of 'cylinder' passes through pipe 35, pilot operated valve 36 or check valve I3 to pipe 12, pipe 13, pipe.11, pilot oper--v ated valve 33, pipe 32, bush 30 and pipe 24 to pump I3.

meer sequence v. sequenced, see Fig. 5.--Shift change--lfiilot operated valves 39, d, ifi and 3 in forward, and'piston operated valves te; and

lil in reverse.

from reverse to forward quadrants- Rinne speed low, no pitch` agences l i i l 'i system induced-shift from forward to reverse ouladrarlt-i--Engine speed low, pitch Vchag through zero" to increasing outward or reverse pitchi--Pilot operated valves et, tu, lf3, '33 and The blades d have been operating in reverse.

and it is desired to change to forward operation.

.idd in reverse, and piston operated valves 3d,

ld, 68 and it@ in forward.

IThe engine running slow, governor controlled x valve H23 permits'flow from pump 825 and pipe t The pilot releases rod 3 permitting spring 2 f to draw rod l and attached valve arrnsl e, moves the valves 33, 16, 56 and Seto the forward position, while the piston operated valves l@ and 36, are in reverse position. If the engine is slow there Ywill be no change.

in position of the blades 56 as oil from therlght ld, pipe M3, valve 52d, pipei2, bush l, pipe ai, valve it, pipe 'it and pipe- 35, to dead end atvalves 3%,38 and 3d. 'l

' At the same time a governor shunting circuit is open through pipe itt, bush i3d, pipe idd. valve hand side of the pump ill. which is the low engine speed side, although it could pass through pilot operated valve 'ld and pipe i3 and pipe l2, cannot pass pilot operated valve SE. checl:` valve e8 or piston operated valve l.V

The oilwi-ll, therefore,

'I'he other side of pump i@ will draw through check valve 88 from pipe 9i and oil sump'. End of Sequence 8. A Sequence 9, see Fig. 5.Shift from reversel to forward quadrant. Engine speed high, pitch changing through zero to increasing forwardpitch-Pilot operated valves 3d, S5, itl and 33, in

forward, and piston operated valves 36 and l@ in reverse moving to forward. l

If the engine is fast or is speeded, oil from the left-hand, or high engine speed-side Aoi' pump I0 will pass through pipe 2d, bush 36, pipe 32. pilot-operated valve 3, pipe 85, piston-operated valve 38 or pilot-operated valve 39 and pipe di to the inboard or .forward operating. side of cyl inder d5, moving-piston d5 and associated parts 152, 55, 5t, 58 and di to edect turning of the blades toward theforward quadrant,` oilfrom the outboard end. of cylinder ill returning to the pump through check valve t@ etc.

As piston d5 and blades 5d pass through zero position, piston operated. valves l@ and 36 will l be shifted to position of forward operation.

Before the above shift oi piston operated valves vlil and 38, oil from outboard side of cylinder da 2i) be discharged through pressure release valve 8l to pipe Si and oil sump.

idd, pipe idd, valve 55u, pipette, valve it@ and through valve channel l'i, forcing hinged segment u from the face of channel E51 outward f and cutting across mouth |59, blocking now tol `or from pipe d5. Flow passes through always u 1 open mouth it@ and pipe H65, to outboard or re verse operating side of cylinder 4d' forcing piston l d5 in the reverse direction.

v Flow from the inboard, orforward' operating: f side of cylinder msses through pipe idf, alwaysi'-- open mouth 'iid of valve l'if, mouth B73, pipe di,

check valve se, pipe se, valve is, pipe el, buse i82,'pipe tt, pipe ft2, valve 38, pipe it@ and pipe @l to oil sump or tank.-

` mouth H3, permitting free -:flowini either'direc cannot pass through pilot operated valve 66 or piston operated valve 7E.

l@ and 3S oil can pass either into'or out of outboard end of cylinder idithrough piston operated valve. lil permitting normal plus or minus oper-1V Vation in the forward quadrant.

End of Sequence 9. Y It would appear from the preceding sequences that pressure relief valve ii@ and check valve t5 have no function in Figs. l, 2, '3, d and 5 and could r be dispensed with. They are included, however,`

" only during shift of the blades E@ from quadrant After above shift or the piston operated valves 5,0

As the piston ,t5 and blades Si? pass. zero,

valve iet, in the governor shunting system. is

closed, permittinghinged segment i12 of Avalve il@ toswing against mouth lli and from across tion between pipes di and ii i Fig. 3.

End of Sequence l0.

Sequence 11, see Fig. 3.-Governor shunting system included-Shift from reverse to 'forward quadrant-Engine speed low, pitch changing through "zero" to increasing outward or forward pitch-#Pilot-operated valves 3Q, iid, lill.V d3 d idd in.- forward, and piston-operated valves 3B,

l. it@ and i in reverse.

The engine being slow, governor-controlled l valve lll permits now from pipe me, pipe 8d3, valve t28, pipe ire, bush m2, pipe 8l, valve le, pipe 'i3 and pipe i2 and it.

. .et the same time pressure `may travel through` pipe ldd, bush i3d, pipe idd, valve it, pipe itt. valve Het, pipe itt, valve l'l, valve-channel lil,

forcing hinged segment H2 across mouth H3 v v and eifectually closing connection to pipe d i Oil pressure continues through always open mouth iid and pipe tdi to the lnboard or forward .operating end of cylinder tid, forcing piston. d5 forward. Oil from the outboard side of cylinder dd passes through pipe E65, into valve l5@ through always open mouth i ad, mouth S, pipe 65, vcheck valve tu, pipe 72, pipe it, valve 'ld,`

pipe Si, bush 82, pipe iil, pipe M2, valve E33,

pipe l@ and pipe @i to oil sump or tank.

to quadrant and as it does not otherwise aect 1 the functioning of the system described in the preceding sequences, its operation will bedescribed only during such shifting.

Seq/tence 10, `see Fig. 6.4overnor shunting As piston de .passes zero position; valves ld, iw, le and @t are shifted to forward operatingv positlon, closing governor shunting oil ow r through pipe I6Q,'etc.,'perxnitting hinged segment i12 of valve im to swing against mouth of channel ill, opening mouth lf3 connected to pipe di and permitting free flow in either direction between pipe 'di and pipe lili.

This system is now adapted to operatel as in Fig. 1.

End of sequence 1l.

Figs 'i and la illustrate the' special valves lit and itil. itl is the body of the valve it@ or ilu;

The system is now in positionto operate as in to dead end at valves te, ttl

l and of interior of valve body |03 is an always open fitting and |50 the mouth thereof, fluid or gas passing through which meets with no obstruction; |05 is a fitting connecting with mouth |59, the face I |0 of which is finished in a. piane parallel with the flat, finished surface |08 of a hinged segment |58. Hinged segment |58 may rest upon face ||0 or surface of the valve body interior. Hinged segment |58 is provided with a hole ||2 by which 'it is swingably mounted on a pin ||3 which is attached in the vvalve body IUI. At 90 to surface |08 of segment |58 is a surface ||4 which normally rests against the mouth face ||6 of a fitting ||1 defining the channel or mouth |51, the face I6 of said mouth |51, forming a reasonably fluid tight t with the surface IH. Face ||6 of mouth |51 is finished in a plane parallel with surface |4 of segment |58. A spring ||8 on a pin ||9 attached in valve body Ill!y in contact with wall of valve interior and outer surface |2| of segment |58 may be used, if desired, to insure contact of surface ||4 of. segment |58 with mouth face ||6. When in this position segment |58 may rest upon portions ||0 The whole is enclosed in any desired manner as by a cover |22, Fig. '1. y

The operation of the valve |55 or |10 just described is as follows:

Mouth |60 is always open furnishing an unobstructed passage to fluid. Mouth |59 is normally open except when fluid from mouth |51 forces surface Hd of segment |58 away from said mouth, causing surface |08 of segment |58 tc cross face I0 of mouth |59 forming a. reasonably fluid tight contact therewith, and thus providing free passage for fluid or gas from the mouth |51 to mouth |86.

I claim:

1. In the combination of a controllable pitch propeller and a shaft for driving said propeller; means for mounting the blades permitting variation of the pitch thereof; means for varying the pitch of said blades comprising a, fluid motor for shifting said blades and a means for controlling the direction of operation of said motor, said control means including a governor, operable in accordance with the speed of the propeller shaft, controlling a set of valves; a second set of valves controlled in accordance with the position of the blades; a third set of manually controlled valves; and a valve controlled by the flow of fluid independent of the governor; engine throttle valve control means operated by the governor to close the throttle valve on excessive speed of the engine; and means to shut-off the ignition of the engine on extremely excessive speed of said engine.

2. In combination, a hub, propeller blades mounted on the hub for change of their pitch; a fluid motor connected to said blades for change of their pitch; at least one pump; a speed governor; at least one governor actuated valve; a manually operable set of valves; a set of valves operabl with the blades; all of said valves being arrange to form a governor controlled system in which there is a valve actuated with the blades to close a passage to the outboard side of the motor; a manually operable valve to close a parallel passage to the outboard side of the motor; a check valve in ai parallel passage to the outboard side of the motor arranged to permit fluid flow only from and not to the outboard side of the motor; a valve actuated with the blades to CTI a manually operable valve to close a parallel passage to the inboard side of the motor; and a check valve in a parallel passage to the inboard side of the motor arranged to permit flow only from, and not to, the inboard side of the motor, whereby governor controlled blade movements in either direction occur within a range of pitch angles appropriate to the position of the manually operable set of valves.

3. In combination: a hub; propeller blades mounted on the hub for change of their pitch; a fluid motor connected to said blades for change of their pitch; at least one pump; a speed governor; at least one governor actuated valve; a manually operable set of valves; a set of valves operable with the blades; all of said valves being arranged to form a governor controlled system. and a system independent of the governor; said governor controlled valve system including a valve actuated with the blades to close a passage to the outboard side of the motor; a manually operable valve to close a governor controlled parallel passage to the outboard side of the motor; a check valve in a third parallel passage to the outboard side of the motor arranged to permit fluid ow only from the outboard side of said motor; a v'alve actuated with the blades to close a passage to the inboard side of the motor; a manually operable valve to close a parallel passage to the inboard side of the motor; a check valve in a parallel passage to the inboard side of the motor arranged to permit fluid flow only from the inboard side of the motor whereby governor controlled blade movementspin either direction occur within a range of pitch angles appropriate to the position of the manually operable set of valves; a pump in said valve system independent of the governor; a passage not controlled by the governor with a manually operable valve therein; two valves operable with the blades and connectable with said passage, each of said v`valves being connectable with the motor through a` special valve which prevents diversion of the fluid flow from between said valve and said motor; one of said valves being always open to connection with said passage and the other being always closed to connection with said passage; said valves, being in such positions that when the propeller blades are in a range of pitch angles other than that appropriate to the position of vthe manually operable set of valves, fluid may pass through s'aid passage to operate the motor to bring said blades into zero pitch angles; and the pitch of said blades being controllable by fluid flow through the governor controlled valve system when said valves are in a range of pitch angles appropriate to the position of the manually operable set of valves.

4. In combination: a hub; propeller blades mounted on the hub for change of pitch; a, fluid motor connected to said blades for changing their pitch; at least one pump; a system of conduits between said pump and motor comprising three passages; valves in two of said passages; a speed governor controlling said valves; a manually operable set of valves in said passages for reversing the direction of the ow of fluid from said pump to said motor; two valves connectable with the third of said passages, which third passage is not controlled by said governor; means connecting said two valves with the motor, one of said valves being always open to said third passage and the other always closed to said third close a passage to the inboard side of the motor; passage; said valves being in such positions that when the blades are in a range of pitch angles other than that appropriate to the position of the manually operable set of valves, fluid may pass through said third passage to operate the motor to bring the blades into a range of pitch angles appropriate to the position of the manually operable valves; the pitch of said blades being controllable by uid ilowing through the governor controlled valves when said blades are in a range of pitch angles appropriate to the position o the manually operable set of valves.

5. In combination: a hub; propeller blades mounted on the hub for change of pitch; a iluid motor connected to said blades for changing their pitch; at least one pump; a system of conduits between said pump and motor comprising three passages; valves in two of said passages; a speed governor controlling said valves; a manually operable set of valves in said passages for reversing the direction of the flow oi' uid from said pump to said motor; two valves connectable with the third of said passages, said third passage not being controlled by said governor; means connecting said two valves with said motor, oneof said valves being always opentc said third passage and the other always closed to said third passage, said valves being in such positions that when the blades are in a range of pitch angles otherthan that appropriate to the position of the manually operable set of valves, fluid may pass through said third passage to operate the motor to bring the blades into the pre-set minimum governor controlled pitch angles; and the pitch of said blades being controllable by fluid flow through the governor controlled valves when said blades are in a range of pitch angles appropriate to the position of the manually operable set of valves.

6. In combination, a hub; propeller blades mounted on the hub; a fluid motor connected to the blades for changing their pitch; at least one pump; a system of conduits between said pump and motor comprising three passages; a governor; at least one valve controlled by said governor and regulating the fluid flowing in two of said passages; a manually operable set of valves in said passages f or reversing the direction of iiuidiiowing from said pump to said motor; a set of valves in said passages operable with the blades to prevent blade movement to a range of pitch angles other than that appropriate tothe manually 'F operable set of valves; check valves to permit outward ilow of uid from the respective ends of the motor; two valves connectable with the third of said passages, which third passage is not controlled by the governor; means connecting said last mentioned two valves with said motor, one of said valves being open to said third passage when the other is closed to said third passage; said valves being in such positions that, when the blades are in the range of pitch angles other than 'that appropriate to the position of the manually operable set of valves, iluid may pass through said third passage, and through a valve operable by ilow from said third passage to close an otherwise open passage, and through a passage to the motor to operate said motor to bring the blades into zero pitch angles; and the pitch of said blades being controllable by fluid flowing through the governor controlled valves when the blades are in a range of pitch angles appropriate to the position of the manually operable set of valves.

'7. n combination a hub, propeller blades mounted on the hub for change of pitch; a ud motor connected to said blades for changing their pitch; a pump; a speed governor controlling operation of the pump; a system of conduits between said pump and motor comprising two passages; check valves in said passages for controlling outward iiow from the respective ends of the fluid motor; a manually operable set ci valves in the system for reversing the direction of the ow of uid from said pump to said motor; two other valves, in the system, operatively controlled in accordance with the position of the propeller blades, for connecting said two valves .with the fluid motor, one of said valves being open to said passage when the other is closed to said passage; said respective valves being in such positions that when the blades are in a range cfpitch angles other than that appropriate to the position of the manually operable set of valves, iiuid may pass through one of the passages to operate the motor to bring the blades into a range of pitch angles appropriate to the position of the manually operable valves, and the pitch of said blades being controllable by fluid flowing through the valves when said blades are in a range of pitch angles appropriate to the position of the manually oper able set of valves.

8. The combination of claim '7, wherein the pump is of the reversible pressure type including a unidirectional rotor; circumferentially spaced radial cylinders in said rotor; pistons in said cylinders operatively coupled to a common shifter: and means whereby said shifter is vertically movable under control of the governor to effect reversal of the pressure flow through the pump.

9. In combination, a controllable pitch propeller, a hub; blades mounted thereon; a governor; uid pressure supply means controlled by the governor to vary the flow of said iiuid pressure;

- valve means manually operable to select the de- 'sired pitch angle range; valve means operable with the blades and cooperative with said manually operable valve means to limit two-directional blade movement to the pitch angles appropriate to the position of the manually operable valve means; and check valve means effective to permit other blade movement only toward the pitch angles appropriate to the position of said manually 'operable valve means.

10. In combination, in a controllable pitch propeller, a hub; blades mounted thereon; a governor; iiuid pressure supply means controlled by the governor to vary the flow of said uid pressure; fluid pressure supply means independent o.' the governor; manually operable adjustable valves to select the desired pitch angle range; valves operable with the blades and cooperating with the aforesaid manually operable valves to limit the automatically variable blade movement to the pitch angles appropriate to the position of the manually operable valves as adjustably preset, for example the minimum negative automatically variable pitch.

11. In combination, in a controllable pitch propeller, a hub; blades mounted thereon for variation oi the pitch angles; a governor; a fluid motor connected to said blades for varying their pitch; a pressure iiuid supply means operative to accomplish change of pitch angles under control of the governor; a pressure uid supply line to accomplish change of pitch angles independently of the governor; manually operable valve means to reverse the direction of the application of power to change the pitch angles; valves operable with the blades and cooperating with the manually operable valve means to limit control, within any desired range of pitch angles, of the gow respect to zero. Y 12. In combination, in a controllable pitch pro- A peller. a hub; propeller blades mounted thereon the said manually operable valves.

independent of governor control for changing said ranges of pitch angles, which may be of any desired minimum and maximum magnitude with for change of their pitch; a speed responsive governor; a fluid motor with associated means, connected to said blades, f or changing their pitch; a pressure fluid supply line controlled by the 'f speed responsive governor; a pressureuid supply line independent of the governor;` manually operable valves Vto select the desired range of pitch angles by reversing the direction of the pressure iiuid owing to the motor when it is so desired; valves operable with the blades and cooperating with the said manually operable valves for actuating the motor, independently of governor control, to effect movement from without the range of pitch angles appropriate to the position of the said manually operable means to within a pre-selected minimum ofthe pitch ranges appropriate to the position of said manually operable means; and means for application of governor controlled power within the automatically variable pitch ranges appropriate to the 13. In combination, in a controllable pitch propeller, a hub; propeller blades mountedthereon for .change of their pitch; a motor connected to said blades for changing their pitch; a speed re-` sponsive governor; a Power supply to the motor controlled by said speed responsive governor; a power supply to said motor independent of the governor control; manually operable means in the iirst mentioned supply to select the desired range of pitch angles by reversingl the direction of power supply to the motor when it is so desired; means operable with 'the blades and coposition of` 2,307,849 ernor controlled pressure fluid supply, and means the position of the manually operable means; and means for application of governor controlled power within the automatically variable pitch ranges appropriater to the position of the said manually operable means. Y f

14. In combination, in a controllable pitch propeller, a hub: propeller blades mounted thereon for change of their pitch: a iluid motor conently ci' the governor to the motor for eii'ectingl movement ofthe propeller-blades, from without 'to within, the pre-selected minimum pitch ranges appropriate to the position of said manually opl tor foreiecting other movements within the au- Verable means: and means to effect application of governor controlled'pressure uid to the motomatically variable pitch ranges appropriate to the position of the said manually operable valves.

15. In combination, in a controllable pitch propeller, a hub; propeller blades mounted thereon'for change of their pitch;`a iiuid motor connected to said' blades for changing their pitch; a

' speed responsive governor; a pressure fluid supply line controlled by the speed responsive gevernor; manually operable valves to select the desired range of pitch angles; valves operable with the blades and cooperating with said manually yoperable -valves for controlling supply of governor controlled pressure iiuid to the motor for. -I

operating with the said manually operable means for application of powerto the motor, independent of the governor, .to produce movement of the blades from without the range of pitchangles appropriate to the position ot the said manually operable means to within apre-selected minimum of said pitch ranges, and appropriate to effecting blade movements within the automatically variable pitch rangeg appropriate-to the position of the said manually operable' means; and means for effecting movement of said blades from outside the pitch ranges appropriate to the position of 4the said manually operable means only toward said pitch ranges appropriate to the position of the manually operable valves.-

MILTON R. MULLEN. 

